The repetitive behavior of a device or system can be described in two ways: a detailed description of one iteration of the behavior, or a summary description of the behavior over many repetitions. This paper describes an implemented program called AIS that transforms the first type of description into the second type. AIS deals only with behavior where each repetition changes parameters by the same amounts. At present, the summary consists of the symbolic average rates of change in parameter values and information on how those rates would be different if various constants and functions had been different. Unlike some other approaches, AIS does not require that a repeating behavior be described in terms of a set of differential equations. Two examples of running AIS are given: one concerns the human heart, the other a steam engine.